At any Navy or advanced base, the electrical system
consists of three parts: the power plant that supplies the
electrical power, the distribution system that carries the
electrical current from the generating station to the
various buildings, and the interior wiring systems that
feed the electrical power to the appliances and
equipment within a building.
As defined here, interior wiring begins at the point
where the distribution systems service leads are
connected to the wiring from within the building and
extends through each circuit of the interior wiring of the
building to the last fixture installation.
In this chapter, we will discuss your responsibilities
in meeting various code and specification requirements
and a variety of techniques for installing, repairing, and
maintaining interior wiring systems.
The National Electrical Code© (NEC©) is
prepared and published every 3 years by the National
Fire Protection Association (NFPA). You should use
the latest publication and volume reference. The NEC©
is an accepted guide for the safe installation of electrical
conductors and equipment. Its purpose is to safeguard
personnel and buildings and their contents from hazards
arising from the use of electricity. NAVFACENGCOM
recognizes the NEC© and uses it as its minimum
How does the NEC© minimize the dangers
mentioned above? Briefly, the NEC© provides the
Various methods of wiring and descriptions of
Techniques for wiring designs and protection
Requirements of general and special equipment
Special conditions and occupancy information
A variety of tables and examples for calculations
The NEC© is a wealth of information that provides
CEs with a strict to-be-observed guide that experience
has shown minimizes electrical hazards to personnel
and buildings and their contents.
Now, we are going to distinguish between three
important electrical terms. As a CE, you will need to
know the difference between the terms grounded,
grounded conductor, and grounding conductor.
Grounded, as defined by the NEC©, means connected
to the earth or to some other conducting body that serves
in place of the earth. A grounded conductor is a circuit
conductor that is intentionally grounded. A grounding
conductor is a conductor used in connecting equipment
in the circuit of a wiring system to a grounding electrode
or electrodes. As a CE, you should make it a point to
learn the difference between these terms. You will see
them and hear them discussed throughout your career.
Use the NEC©, study it, and learn it. A working
familiarity with this reference will prove useful to you,
and, as you advance in rate, teach your junior personnel
the importance of this valuable guide.
SERVICE ENTRANCE AND
The starting point for interior wiring is the service
entrance. It is connected to the service drop. The service
entrance is made up of several components, but before
we get into the specifics concerning the service
entrance, let us look briefly at the wiring system used to
supply a building.
The types of electrical systems that are to be
installed are determined mostly by what the building is
to be used for and the type of equipment that is to be
used. Generally speaking, electrical loads are divided
into four categories:
two-wire, single-phase; three-
wire, single-phase; three-wire, three-phase; and four-
The simplest wiring system is a two-wire, single-
phase type, as shown in figure 5-1. This system is used
Figure 5-1.Two-wire, single-phase system.